Method of producing fiber, and methods of producing electron-emitting device, electron source, and image display device each using the fiber

ABSTRACT

A method of producing a fiber, comprising the steps of introducing catalytic particles originally formed in a particle-forming chamber into an arraying chamber together with a carrier gas, to cause the catalytic particles to become arranged on a substrate disposed in the arraying chamber. A next step includes growing fibers, each including carbon as a major component, based on the catalytic particles arranged on the substrate. The fibers grow by heating the catalytic particles arranged on the substrate in an atmosphere containing carbon.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of producing a fibercontaining carbon as a major component, a method of producing anelectron-emitting device using the fiber, a method of producing anelectron source having a plurality of the electron emitting devicesarranged in an array configuration, and a method of producing an imagedisplay device comprising the electron source.

2. Description of the Related Art

One type of cold cathode device which has been given attention is thefield-emission type (FE type) of electron emitting device which emitselectrons from the surface of a material utilizing the known tunneleffect. As an example of the FE type cold cathode, at least one having acone or quardrangular pyramid shape such as the FE cold cathodedisclosed in the publication entitled “physical properties of thin-filmfield emission cathodes with molybdenum cones”, J. Appl. Phys., 47, 5248(1976), by Spindt, or the like, has been known (hereinafter, referred toas the Spindt type).

In recent years, much attention also has been given to FE type coldcathodes using carbon nanotubes as emitter materials thereof. Withregard to methods of producing electron emission devices using carbonnanotubes, a method of placing previously-produced carbon nanotubes intoa paste material or the like, and arranging them into predeterminedpositions in array configuration is known (see Japanese Patent Laid-OpenNo. 2001-043792; hereinafter, this method is referred to as an indirectarraying method), as is a method of arranging a metallic catalyst indesired positions in an array on a substrate, and selectively growingcarbon nanofibers in areas having the metallic catalyst arrayed thereinby a chemical vapor deposition method (see Japanese Patent Laid-Open No.2000-057934; hereinafter, this method is referred to as a directarraying method).

SUMMARY OF THE INVENTION

In order to produce an image display device using an FE type coldcathode, it is required to achieve a high luminance comparable to thatobtained by a CRT device. Moreover, to reduce the amount of consumedpower, it is required to reduce the drive voltage and increase thequantity of electrons emitted from the cold cathode. Furthermore, it isnecessary for the current quantity distribution per one pixel to besmall, and also for electron-emissions from the cathode andlight-emissions from a fluorescent member to be carried out stably for along time.

To keep the luminance of the above-described type image display deviceat a high level for a long time, considering the service lives of thefluorescent member and cold cathode, it is necessary to increase thenumber of emitters per unit area and reduce emission-currents generatedfrom the respective emitters. Moreover, to reduce the drive voltage, itis required to provide an acute-angular structure such as one like thetop of the Spindt type cold cathode (referred to above), which isfeasible for field-concentration.

The carbon nanotubes have a high aspect ratio, so that the electricfield concentration is easily achieved, and the electron-emission can becarried out at a low voltage. Moreover, the shapes of the respectivecarbon nanotubes are fine, so that the carbon nanotubes can be arrangedin an array and integrated so as to have a high density per unit area.Moreover, the carbon nanotubes are advantageous in that they can beinexpensively produced in a large area by a vapor deposition method orthe like. Thus, carbon nanotubes are attractive and very suitablematerials for cold cathodes of image display devices and the like.

However, according to conventional methods of producing carbonnanotubes, it often is difficult to arrange the carbon nanotubes in anarray regularly and consistently at appropriate intervals, and tocontrol the density of the carbon nanotubes. Moreover, since the carbonnanotubes formed by the conventional methods are arranged less regularlyand consistently, in at least some cases it can be difficult touniformly apply an electric field to the respective carbon nanotubes.Therefore, the electron emission characteristics of the devices canbecome irregular and inconsistent. In at least some cases, the densityof electron-emission points can be low, even if the integration densityof the carbon nanotubes is high.

To successfully use carbon nanotubes in an image display device, it isrequired to control the integration density of the carbon nanotubes andform a configuration such that an electric field can be uniformlyapplied to the carbon nanotubes, and moreover, to increase the number ofelectron emission points (electron emission sites) for increasing thecurrent density per one pixel, while the quantity of electrons emittedfrom the respective tubes is reduced.

The present invention has been conceived to solve the above-describedproblems, and it is an object of this invention to provide a method ofproducing a fiber by which the fiber can be simply and easily formed andin which fibrous carbon substances such as carbon nanotubes and graphitenanofibers (which will be described below) are arranged in an arrayregularly at appropriate intervals and, in which the number of emissionpoints (emission sites) per unit area is increased, the current densityis enhanced, and the service life becomes long. It also is an object ofthis invention to provide methods of producing an electron emissiondevice, an electron source, and an image display device, each using thefiber.

The method of producing a fiber in accordance with the present inventioncomprises employing a gas deposition method by which particles formed ina particle-forming chamber are introduced together with a carrier gasinto an arraying chamber through a transport tube, and the particles arethen arranged on a substrate disposed on a stage in the arrayingchamber, through a nozzle. The method also comprises the steps ofarranging catalytic particles on the substrate, and growing fibers, eachcontaining carbon as a major component obtained from a gaseous phase,using the catalytic particles as nuclei.

The material of the catalytic particles preferably may be selected fromthe group consisting of Pd, Pt, Ni, Co, Fe, Cr, and mixtures of at leasttwo of these materials, and moreover, may contain Pd or Pt as a majorcomponent. The fiber containing carbon as a major component preferablymay be a fiber selected from the group consisting of a graphitenanofiber, a carbon nanotube, an amorphous carbon fiber, and a mixtureof at least two of these materials.

The fibers including carbon as a major component preferably have arelationship defined by the expression W≧½H, and more preferably, W≧2H,in which W represents the average distance between the portions bondedto the substrate of neighboring fibers, and H represents the averagethickness of the fibers.

Moreover, the method of producing a fiber containing carbon as a majorcomponent in accordance with the present invention comprises the stepsof (A) preparing a catalytic material in a first chamber, (B) arranginga substrate in a second chamber, and (C) setting the pressure in thefirst chamber to be higher than that in the second chamber. As a result,the catalytic material prepared in the first chamber is passed throughthe transport tube connecting the first chamber and the second chamberto each other and is caused to collide with the substrate so that thecatalytic material (catalytic particles) is arranged on the substrate. Anext step (D) includes heating the catalytic material (catalyticparticles) arranged on the substrate while the catalytic material(particle) is in contact with a gas containing a carbon compound, andthereby a fiber including carbon as a major component is formed on thesubstrate.

Preferably, the transport tube is connected to a nozzle disposed in thesecond chamber. Also, preferably, the inside of the second chamber ismaintained in a reduced pressure state. The catalytic materialpreferably may be selected from the group consisting of Pd, Pt, Ni, Co,Fe, Cr, and mixtures of at least two of these materials. The fibercontaining carbon as a major component preferably may be selected from agraphite nanofiber, a carbon nanotube, an amorphous carbon fiber, andmixtures of at least two of these materials. Preferably, the fibercontaining carbon as a major component has a plurality of graphenes.Also, preferably, a plurality of the graphenes are laminated in anon-parallel relationship with the axis of the fiber.

Preferably, the catalytic material collides with the substrate in itsparticulate state. Also, preferably, the catalytic material istransported together with the gas introduced into the first chamber intothe second chamber. The gas introduced in the first chamber preferablyis a non-oxidizing gas.

According to an aspect of the present invention, the catalytic particlescan be controlled so as to have a desired density. As a result, fibrouscarbon substances (fibers containing carbon as a major component) can begaseous-phase-grown, and the density of the formed fibrous carbonsubstances can be controlled.

A method of producing an electron-emitting device in accordance with anembodiment of the present invention comprises the steps of forming acathode electrode on a substrate, and forming a plurality of fibers eachcomprising carbon as a major component on the cathode electrode. Thefibers each contain carbon as a major component, and are producedaccording to any one of the above-described methods of this invention.

Also in accordance with an embodiment of the present invention, anelectron-emitting device is provided which comprises a cathode electrodedisposed on a substrate, and a plurality of fibers including carbon as amajor component electrically connected to the cathode electrode. Aplurality of the fibers have a relationship defined by the expressionW≧½H, in which W represents the average distance between the portionsbonded to the substrate of neighboring fibers containing carbon as amajor component, and H represents the average thickness of the fiberscomprising carbon as a major component.

According to another aspect of the present invention, a method ofproducing an electron source is provided, in which a plurality ofelectron-emission devices using fibers, each including carbon as a majorcomponent are formed and arranged in an array configuration. Theelectron-emission devices preferably are produced according to theabove-described method of producing an electron-emitting device.

According to still another aspect of the present invention, a method ofproducing an image display device also is provided, wherein the imagedisplay device includes an electron source and a light-emitting member.The electron source preferably is produced according to theabove-described method of producing an electron source.

Further objects, features and advantages of the present invention willbecome apparent from the following description of the preferredembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, 1C, 1D, and 1E illustrate a basic method of producing anelectron emission device of Examples 1 and 2 to which the presentinvention is applied.

FIG. 2 is a schematic view showing a gas deposition method according toan embodiment of the present invention.

FIGS. 3A and 3B illustrate a method of producing a fiber according tothe present invention. FIG. 3A is a schematic plan view of catalyticparticles formed on a substrate, and FIG. 3B is a schematiccross-sectional view of fibrous carbon substances grown using thecatalyst shown in FIG. 3A as a nucleus.

FIGS. 4A, 4B, and 4C schematically show the structure of a carbonnanotube.

FIGS. 5A, 5B, and 5C schematically show the structure of a graphitenanofiber.

FIG. 6 shows an example of a configuration provided for operation of theelectron-emission device according to the present invention.

FIG. 7 is a plan view of an electron emission device produced accordingto the method of Example 1 of the present invention.

FIG. 8 is a plan view showing an example of the configuration of asimple matrix circuit using a plurality of electron sources produced bya method of the present invention.

FIG. 9 is a perspective view showing an example of the configuration ofan image display panel using the electron sources produced by the methodof the present invention.

FIG. 10 shows an example of a circuit diagram of an image display panelusing electron sources produced by a method of the present invention.

FIGS. 11A, 11B, 11C, 11D, and 11E illustrate the production process foran electron emission device of Example 3 of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, a gas deposition method which is a basis of a method of producinga fiber according to the present invention will be described. The gasdeposition method is carried out by using an ultra-fine particle formingchamber (first chamber), a film-forming chamber (second chamber), atransport tube, and so forth. In the ultra-fine particle formingchamber, for example, a material is heated in an inert gas environmentby arc heating, resistance heating, high frequency induction heating,laser heating, and the like to be melted and evaporated. Thus, theevaporated material collides with the inert gas, so that metallicultra-fine particles (particles of a catalyst) are prepared. Thepreparation of such catalytic particles is not limited to theabove-described method. That is, according to another embodiment of thisinvention, catalytic particles which already has been prepared may besupplied into the ultra-fine particle forming chamber, and dispersed inthe gas present in the ultra-fine particle forming chamber (they are putinto a so-called aerosol state). Then, the ultra-fine particles areintroduced to the film-forming chamber via the transport tube to beejected at a high speed through a nozzle connected to the end of thetransport tube, the high-speed ejection being caused by the differencebetween the pressures in the ultra-fine particle forming chamber and thefilm-forming chamber. Thus, a dry film-forming method is carried out,and thereby, the film is directly formed. From the standpoint of thestability of film-formation, the above-described method in which thecatalytic material is evaporated in the ultra-fine particle formingchamber to collide with the gas, to thereby form the ultra-fineparticles is preferred. Therefore, hereinafter, a case employing themethod in which the catalytic material is evaporated in the firstchamber (as described above) to form the catalytic particles, will bedescribed in detail. However, as mentioned above, the present inventionmay be applied to the method in which the catalytic particles arepre-formed to be used as the catalytic particles in the first chamber,and are introduced into the first chamber to be brought into the statein which the particles are dispersed in the gas (into a so-calledaerosol-state).

On the other hand, to directly arrange the fibrous carbon substances(fibers each containing carbon as a major component) in an arrayconfiguration on a substrate according to a vapor deposition method, themethod according to an embodiment of this invention is generallyemployed in which the catalytic particles as nuclei for growth of thefibrous carbon substances are arranged in an array configurationaccording to the production method of the present invention, andthereafter are heated in an ambient atmosphere of a gas containingcarbon and so forth, and thereby, the fibrous carbon substances aregrown on a region on the substrate in which the catalyst is formed.

According to a conventional method of arranging the catalytic particlesin an array configuration, first a catalytic material is vapor-depositedonto a substrate by sputtering or the like, and thereafter isheat-treated so that the catalytic material becomes granular. Accordingto this conventional method, the particles can be formed at a highdensity. However, when the carbon fibers are grown using the particlesas the nuclei, the above-described problems are caused.

In this invention, the density of the particles for use as the catalystis controlled according to a method to be described below, so that thearray of the carbon fibers at a desired density can be provided.

FIG. 2 is a schematic view showing an apparatus for producing a fiberaccording to an embodiment of the present invention. This productionapparatus is provided with a particle forming chamber (first chamber) 28in which catalytic particles are formed, a particle-arraying chamber(second chamber) 27, a transport tube 21 connecting both of thechambers, and evacuating devices 210 and 211. Thus, in FIG. 2, thesubstrate 1, the transport tube 21, an excess-particle exhaustingmechanism 22, a substrate stage 23, a catalytic material 24, a nozzle25, the particle-arraying chamber (the second chamber) 27, theparticle-forming chamber (the first chamber) 28, a gas-introducingdevice 29, an arraying-chamber exhausting device 210, a forming-chamberexhausting device 211, and a material-heating device 212 are shown.

An example of the process of arraying the catalytic particles on thesubstrate by means of the above-described production apparatus (a firstprocess to a third process) will be described below.

Referring to the first process, the catalytic material 24 placed in thecenter of the forming chamber 28 is given energy by the material heatingdevice 212 to be evaporated. This process is provided for evaporation orsublimation of the catalytic material particles. For this process, forexample, electric furnace heating, resistance heating, high frequencyheating, arc-discharge carried out between opposed electrodes, or anyother suitable techniques, may be used. In this process, the evaporationquantity of the catalytic material 24 is controlled. To suppress theevaporation quantity of the catalytic material 24 to a desired extent,preferably, the material is sublimated at a temperature lower than themelting point thereof.

The subsequent second process is provided for formation of the catalyticparticles. In this process, the catalytic material evaporated in thefirst process is caused to collide with the inert gas introduced intothe forming chamber 28 and is cooled, whereby the material is formedinto particles. In this process, the size of the catalytic particles isdetermined. The size of the particles depends on the number ofcollision-times. Therefore, the size of the particles can be controlledby the pressure of the gas, the distance d from the evaporation portionof the catalytic material 24 to the transport tube 21, the evaporationquantity obtained in the first process, and so forth. As the gas, anon-oxidizing gas is preferably used, such as, for example, an inertgas. Specifically, helium gas is suitable, since the formed particleshave a small size-distribution, although other suitable non-oxidizinggases also may be employed.

In a third process, the catalytic particles formed in the second processare arranged in an array configuration on the substrate 1. In thisprocess, the catalytic particles are supplied to the arraying chamber 27via the transport tube 21 by setting the pressure in the forming chamber28 (the first chamber) so as to be higher than that in the arrayingchamber 27 (the second chamber). Then, the particles drawn into thetransport tube 21 are accelerated and ejected from the nozzle 25 tocollide with the substrate 1 disposed on the stage 23 in theparticle-arraying chamber 27 (the second chamber) and be affixedthereto. The density of the particles arranged in an array configurationon the substrate 1 can be set by controlling the difference between thepressures in the forming chamber 28 and the arraying chamber 27, theacceleration distance of the particles, the distance between the nozzle25 and the substrate 1, the moving speed of the substrate 1, and soforth.

Preferably, the pressure in the second chamber is maintained in thereduced pressure state. The mean free path of the catalytic particlesejected under the reduced pressure state is more than about 1000 timeslonger than that of the catalytic particles ejected under an ordinarypressure (in the atmospheric pressure). Thus, the catalytic particlesare prevented from suffering a scattering effect. That is, for example,the catalytic particles, if ejected under the atmosphere, will bescattered so that kinetic energy is lost. Thus, it is difficult to fixthe catalytic particles onto the substrate 1. In many cases, thecatalytic particles are not fixed to the substrate. However, thecatalytic particles ejected from the nozzle 25 in the arraying chamber27 (the second chamber) maintained in the reduced pressure state, havinga high kinetic energy, can collide with the substrate 1. This kineticenergy is converted to heat energy, which makes a contribution to theaffixing of the catalytic particles onto the substrate 1, which isintended by the present invention.

By controlling the conditions in processes 1 to 3, the catalyticparticles 4 which are to function as nuclei for growth of the carbonfibers (the fibers containing carbon as a major component) can bearranged in an array configuration in the state thereof which ispreferable for a cold cathode (electron emitting device), as shown inFIG. 1 or 3.

Hereinafter, an array of the fibrous carbon substances desirable for thecold cathode (electron emitting device) which can be realized by thepresent invention will be described with reference to FIGS. 3A and 3B.FIG. 3A is a schematic plan view showing the catalytic particles 4deposited on the substrate 1. FIG. 3B is a schematic cross-sectionalview showing the fibrous carbon substances (carbon fibers) grown usingas the nuclei the deposited catalytic particles 4 shown in FIG. 3A. Ifthe distance W between neighboring fibrous carbon substances 5 (orbetween the neighboring deposited catalytic particles 4) is too short,the effect of enhancing an electric field cannot be satisfactorilyobtained, due to the macro-shapes of the respective fibrous carbonsubstances. Therefore, to effectively cause the concentration of theelectric field, preferably, the distance W is set so as to be wide tosome degree. Giving priority to the concentration of the electric field,preferably, the distance W is at least two times the height H of thefibrous carbon substances. In practice, the distance W may be determinedbased on the durability of the fibrous carbon substances, theintegration degree of the electron emission points, and so forth.

An electric field can easily be applied to the respective fibers due tothe above-described array of the fibrous carbon substances 5. Thus, theelectron emission current from the individual fibers can be increased.Accordingly, the density of the electron emission points (electronemission sites) also can be increased. Moreover, advantageously, thevoltage required for the electron emission can be reduced.

Hereinafter, one of the preferred embodiments of the method of producingan electron emitting device according to the present invention will bedescribed in detail with reference to the drawings. The scope of thepresent invention is not limited to the sizes, materials, shapes andsizes, the relative positions, and so forth of the components describedin this embodiment, unless otherwise noted. An example of a method ofproducing an electron emitting device according to the present inventionwill be described sequentially with reference to FIG. 1.

(1) As the substrate 1, quart glass of which the surface is sufficientlyrinsed, glass of which the content of impurities such as Na is reducedand which is partially substituted with K or the like, a laminate formedby laminating SiO₂ onto a substrate such as a soda lime glass or siliconsubstrate by sputtering or the like, and an insulating substrate made ofalumina or ceramics preferably may be employed. A gate electrode (alsoreferred to as a drawing electrode or a gate) 2 and a negative electrode(also referred to as a cathode electrode) 3 is arranged on the substrate1 (FIG. 1A).

The gate electrode 2 and the cathode electrode 3 are electro-conductive,and are formed by printing, known vacuum film-forming techniques such asvapor deposition and sputtering, and photolithography. Materials for thegate electrode 2 and the cathode electrode 3 preferably are selectedfrom, e.g., carbon, metals, metal nitrides, metal carbides, metalborides, semiconductors, and semiconductor metal compounds. Thethicknesses of the above-described electrodes preferably are within therange of from several tenths of nanometers to several micron meters.Preferably, refractory materials, that is, carbon, metals, metalnitrides, and metal carbides are employed. In a case in which thethicknesses of the gate electrode 2 and the cathode 3 are small, whichmay cause an undesirable voltage drop, or in a case where the devicesare used in a matrix array, a metal material with a low resistancepreferably may be used as a wiring, if necessary.

(2) Subsequently, a resist pattern 11 for determining locations in whichthe fibrous carbon substances are arranged in an array configuration isformed (see FIG. 1B).

(3) Next, the catalytic particles 4 are arranged in an arrayconfiguration on the substrate 1 (see FIG. 1C). As shown in FIG. 2, thesubstrate 1 is placed on the stage 23 in the arraying chamber 27. Thecatalytic material 24 is evaporated in the forming chamber (the firstchamber) 28 having a gas introduced therein. The material for thecatalytic particles 4 preferably is selected from metals which functionas a catalyst for growth of the fibrous carbon substances, such as Pd,Pt, Ni, Co, Fe, Cr, and their mixtures. Referring to the method ofevaporating the catalytic material, one of electric furnace heating,resistance heating, high frequency heating, arc-discharge using opposedelectrodes, or any other suitable technique for evaporating thecatalytic material may be used. Preferably, the catalytic material 24 issublimated at a temperature lower than the melting point thereof.

The evaporated catalytic material collides with the gas in the formingchamber 28 to be formed into particles. As the gas, a non-oxidizing gaspreferably is used. Preferably, the gas is selected from rare gases suchas He and Ar, N₂, and the like. The pressure of the gas in the formingchamber 28 preferably is selected so as to be within the range of 10² Pato 10⁶ Pa, and even more preferably within the range of 10⁴ Pa to 10⁵Pa. A distance d between the evaporation portion of the catalyticmaterial 24 and the transport tube 21 preferably is set so as to bewithin the range of several-tenths of a millimeter to several thousandmillimeters, and even more preferably within the range of severalmillimeters to several ten millimeters.

The catalytic material formed into particles in the forming chamber 28is drawn into the transport tube 21, and accelerated. The particles areejected from the nozzle 25, and fixed to the substrate 1, caused by thedifference between the pressures in the forming chamber 28 and thearraying chamber 27. In some cases, the catalytic particles 4 arearranged in an array configuration on a desired region on the substrate1, caused by the movement of the substrate 1. The pressure of thearraying chamber 27 (the second chamber) preferably is set so as to bewithin the range of 10⁻⁴ Pa to 10⁴ Pa, and more preferably within therange of 10² Pa to 10³ Pa. The aerosol of the catalytic particles (thegas in which the catalytic particles are dispersed) is ejected from thenozzle 25 at a flow rate of, preferably, 0.1 l/min. or higher, and morepreferably, 1 l/min. or higher, toward the substrate 1. Furthermore, thecatalytic particles are ejected from the nozzle 25 at a velocity of,preferably, 0.1 m/sec. or higher, more preferably, 1 m/sec. or higher,and most preferably, 10 m/sec. or higher, toward the substrate 1. Thepressures in the first chamber and the second chamber are set so thatthe above-described flow rate and velocity can be realized. Moreover,the distance between the nozzle 25 and the substrate 1 preferably is setto be 10 cm or less, and more preferably, 1 cm or less. The shape of thenozzle 25 may be optional. Preferably, the nozzle 25 is quadrangular.Nozzles of a multi-nozzle type having a plurality of openings and a slittype are available. The size of the nozzle 25 is determined depending onthe relationship between the region where the catalytic particles are tobe formed and the acceleration of the gas. The area of one nozzlepreferably is selected to be within the range of 10⁻⁶ cm² to 1 cm². Themovement speed of the substrate 1 preferably is set to-be, e.g., withinthe range of 0.1 mm/sec to 10³ mm/sec. Moreover, the distance L betweenthe substrate 1 and the nozzle 25 preferably is set to be within therange of several tens of micronmeters to several centimeters.Preferably, the distance L is set to be 10 cm or less, and morepreferably, is set to be 1 cm or less. In a case in which adhesion ofthe catalytic material to the substrate 1 becomes a problem, thesubstrate 1 is heated (several hundreds ° C.) for enhancement of theadhesion.

The density of the particles can be determined by controlling theabove-described conditions. Especially, the density is affected by theevaporation amount of the catalytic material 24 in the forming chamber28, the shape of the nozzle 25, and the movement speed of the substrate1.

(4) Subsequently, the resist 11 is removed by means of a remover or thelike, so that the unnecessary catalytic material is lifted-off (see FIG.1D). In this embodiment, the positions in which the catalytic particles4 are formed are determined by use of the resist pattern. However, theshape of the nozzle 25 and the movement pattern of the substrate 1 maybe set so that the particles are fixed directly onto a required region,without using a mask or the like.

(5) Next, the fibrous carbon substances 5 are formed using the catalyticparticles 4 as nuclei (see FIG. 1E). The fibrous carbon substances 5preferably are formed utilizing a vapor deposition method (CVD method).The shape of the fibrous carbon substances may be controlled by, e.g.,the type of gas used in the CVD method, a gas-decomposing means, a flowrate, crystal-growth temperature, and the shape and material of thecatalytic particles 4.

In the present invention, it is preferred that fibrous carbon substancesformed by decomposing an organic (hydrocarbon) gas and growing by use ofa catalyst be used. As used herein, the term “fibrous carbon substance”means a columnar substance containing carbon as a major component or alinear substance containing carbon as a major component. Also, the term“fibrous carbon substance” means a fiber containing carbon as a majorcomponent. For example, the “fibrous carbon substance” may include acarbon nanotube, a graphite nanotube, an amorphous carbon fiber, and acarbon nanohorn having such a structure as is formed by closing one endof the carbon nanotube. The graphite nanofiber is most preferable as amaterial for a cold cathode (electron emitter).

FIGS. 4A to 4C and 5A to 5C illustrate examples of fibrous carbonsubstances formed by decomposition of an organic gas using a catalyst.In these drawings, FIGS. 4A and 5A on the left sides in these drawingsschematically show the forms of fibrous carbon substances observed on anoptically microscopic level (magnification of up to 1000). FIGS. 4B and5B in the middle of the drawings schematically show the-forms thereof asseen at a scanning electron microscopic (SEM) level (magnification of upto 30,000). FIGS. 4C and 5C on the right side schematically show theforms of the carbon substances observed at a transmission electronmicroscopic level (TEM) (up to 1,000,000).

The fibrous carbon substance in which the graphenes form a cylindricalshape as shown in FIG. 4C is referred to as a “carbon nanotube” (thesubstance in which the graphenes form a multiple-cylinder structure isreferred to as a “multi-wall nanotube”). Especially, in the case of thegraphene having a structure in which the tube top is opened, thethreshold voltage for electron emission is lowest.

FIG. 5C shows the fibrous carbon substances which are formed at arelatively low temperature. In some cases, a fibrous carbon substance ofthis form is called a graphene laminate (for this reason, the laminatealso is referred to as a “graphite nanotube”). More specifically, the“graphite nanotube” means a fibrous substance in which graphenes arelaminated in the longitudinal direction of the fiber (the axialdirection of the fiber). In other words, as shown in FIG. 5C, the“graphite nanotube” is a fibrous substance in which the graphenes arearranged in a non-parallel relationship with the axis of the fiber.

On the other hand, the “carbon nanotube” is a fibrous substance in whichthe graphenes are arranged substantially in parallel with the axis ofthe fiber.

One sheet of graphite is referred to herein as a “graphene” or a“graphene sheet”. Graphite comprises a plurality of stacked or layeredcarbon planes. Each carbon plane preferably comprises a repeated hexagonhaving a carbon atom at each vertex thereof and having a covalent bondalong each side thereof. The covalent bond is caused by sp2 hybridorbitals of carbon atoms. Preferably, the distance (interval) betweenthe neighboring carbon planes is maintained at approximately 3.354 Å.One sheet of the carbon plane is also referred to herein as a“graphene,” or a “graphene sheet”.

The thresholds for electron emission of both types of the fibrous carbonsubstances are about 1V/μm to 10V/μm, so the carbon substances arepreferable characteristics for materials used as an emitter (an electronemission member) according to the present invention.

The electron emitting device using the graphite nanofibers (which deviceis not limited to one having a structure such as that shown in FIG. 6),can cause electron emission by application of a low electric field, andtherefore, a high emission current can be achieved. The electronemission device using the graphite nanofibers also can provide an easymanufacturing method and a stable electron emission characteristic. Forexample, the electron emitting device can be provided by using thegraphite nanofibers as an emitter, and disposing an electrode forcontrolling the electron emission from the emitter. Moreover, alight-emitting apparatus can be provided by using a light-emittingmember from which light is emitted in response to the member beingirradiated by electrons emitted from the graphite nanofibers.Furthermore, an image display device such as a display can be formed byarranging in an array a plurality of the electron-emitting devices usingthe above-described graphite nanofibers, and preparing an anodeelectrode having a light-emitting member such as a phosphor. Theelectron emitting device, the light-emitting device, and the imagedisplay device each using the graphite nanofibers can stably performelectron-emission, even if an ultra-high vacuum condition is notmaintained inside of each device, in contrast to a conventional electronemission device. Furthermore, the electron emission can be carried outby use of a low electric field. Thus, the devices having a highreliability can be produced easily.

The above-described fibrous carbon substance can be formed bydecomposition of a gas containing carbon (preferably, a hydrocarbon gas)using a catalyst (i.e., a material for promoting the deposition of thecarbon). Regarding the carbon nanotube and the graphite nanofiber, thetypes of catalysts and the decomposition temperatures preferably aredifferent from each other.

Fe, Co, Pd, Ni, Pt, and their mixtures are preferably used as thecatalytic material.

With Pd and Ni, the graphite nanofiber can be formed at a lowtemperature (400° C. or higher). The temperature at which the carbonnanotubes can be formed with Fe and Co should be 800° C. or higher.Thus, the formation of the graphite nanofiber using Pd and Ni ispossible at a low temperature, and therefore is preferable in view ofinfluences over other members (such as the substrate 1 and the electrode3) and the manufacturing cost.

Moreover, with regard to Pd, palladium oxide can be used as anuclei-forming material, utilizing the characteristic that the palladiumoxide can be reduced at a low temperature (room temperature) byhydrogen.

For example, the above-described hydrocarbon gas may be selected fromhydrocarbon gases such as ethylene, methane, propane, propylene, andacetylene, or in some cases, may be selected from vapors of organicsolvents such as ethanol and acetone.

In accordance with an embodiment of this invention, the electronemitting device of this embodiment produced as described above is set ina vacuum apparatus 60 as shown in FIG. 6. The air is sufficientlyevacuated from the vacuum apparatus 60 by means of a vacuum-pumpingdevice 63 until the pressure reaches about at least 10⁻⁵ Pa. As shown inFIG. 6, an anode 61 is provided at a height h from the substrate 1, thatis, preferably in a position where the anode 61 is separated by severalmillimeters from the substrate 1. Then, high voltage Va of severalkilovolts is applied to the anode 61.

A fluorescent member (phosphor) 62 coated with an electroconductive filmis disposed in contact with the anode 61. A pulse voltage, that is, adrive voltage Vf of about several tenths of volts is applied to theelectron emitting device, and a flowing device-current If and anelectron emission current Ie are measured.

As a result, isoelectric lines 66 are formed as shown in FIG. 6. Themost concentrated region of the electric field lies at the positiondesignated by reference numeral 64 which is nearest to the anode in thecold electrode 5 and is inside a gap between elements 2 and 3.

An image display device can be formed by arranging in an arrayconfiguration a plurality of the electron emitting devices preparedaccording to the present invention as shown in FIG. 6.

Hereinafter, specific examples with respect to the embodiment of thepresent invention will be described in detail.

EXAMPLE 1

FIGS. 1A to 1E represent steps of a method of producing an electronemitting device in Example 1 of the present invention. FIG. 7 is a planview showing the prepared electron emitting device. In FIG. 7, referencenumeral 5 designates the region in which the fibrous carbon substancesare formed. The production process for the electron-emitting device inthe Example 1 will now be described below.

(Process 1)

A quartz substrate is used as the substrate 1, and sufficiently rinsed.Ti with a thickness of 5 nm, Pt with a thickness of 50 nm, and Ti with athickness of 5 nm are vapor-deposited on the substrate in this order asa gate electrode 2 and a cathode 3 by photolithography and sputteringmethods (see FIG. 1A).

(Process 2)

Next, a resist pattern 11 is formed using a negative photoresist (seeFIG. 1B).

(Process 3)

Subsequently, catalytic particles 4 are arranged by a gas depositionmethod. As shown in FIG. 2, a substrate 1 is disposed on a stage 23 inan arraying chamber 27. Pd as the catalytic material 24 is placed on aW-boat in a forming chamber 28 having He gas introduced therein, andheated to about 1400° C. by resistance heating to be sublimated. Theconditions for the formation and arranging of the particles in an arrayare as follows.

Pressure in forming chamber: 50000 Pa

Pressure in arranging chamber: 100 Pa

Distance d between evaporation portion and transport tube: 10 mm

Shape of employed nozzle: 0.3 mm×5 mm

Movement speed of stage: 10 cm/sec

Distance L from outlet of nozzle to substrate: 10 mm

The catalytic particles 4 with a size of about 30 nm are arranged in anarray at intervals of about 1 μm on the substrate 1 (see FIG. 1C).

(Process 4)

Subsequently, the resist 11 is peeled by means of a remover so thatexcess Pd is removed by the lift-off method. (see FIG. 1D)

(Process 5)

The heat treatment is carried out at 500° C. for 10 minutes in a gasstream (atmospheric pressure) containing 0.1% of ethylene diluted innitrogen gas. Thus, the cold cathode 5 comprising fibrous carbonsubstances each containing the Pd particle as a nucleus, and having adiameter of about 20 nm to 30 nm is formed. Then, the thickness of theindividual fibrous carbon substances is about 1 μm. The fibrous carbonsubstances are graphite nanofibers as represented in FIGS. 4B and 4C(see FIG. 1E). A plurality of the fibrous carbon substances formed inthis embodiment are bending.

EXAMPLE 2

Hereinafter, Example 2 will be described, in which fibrous carbonsubstances having different qualities are formed in a manner similar tothat in Example 1.

(Process 1)

The gate electrode 2 and the cathode 3 are formed on the quartzsubstrate 1, and thereafter, the resist pattern 11 is formed in a mannersimilar to the processes 1 and 2 in Example 1 (see FIG. 1A and FIG. 1B).

(Process 2)

The catalytic particles 4 are arranged in an array by the gas depositionmethod in a manner similar to the process 3 of Example 1. The conditionsunder which the particles are formed and arranged in an array are asfollows.

Means for evaporating catalyst: resistance heating sublimation method(heating at 1400° C.)

Raw material for catalyst: mixture of Pd and Co

Pressure in forming chamber: 20000 Pa

Pressure in arraying chamber: 100 Pa

Distance d from evaporation portion to transport tube: 10 mm

Shape of employed nozzle: 0.3 mm×5 mm

Movement speed of stage: 10 cm/sec

Distance L between outlet of nozzle and substrate: 10 mm

The catalytic particles 4 with a size of about 10 nm are arranged in anarray on the substrate 1 at intervals of about 1 μm under theabove-described conditions (see FIG. 1C).

(Process 3)

Subsequently, the resist 11 is peeled off by use of a remover, so thatexcess Pd and Co are removed by the lift-off method (see FIG. 1D).

(Process 4)

A substrate is placed into a tightly-closed chamber. Then, the CVDmethod is carried out in a gas stream (2×10³ Pa) containing 1% ofethylene diluted in hydrogen gas. The cold cathode 5 comprising thefibrous carbon substances each formed using the particle as a nucleus,having a diameter of about 20 nm and a high directivity are formed. Inthis case, the fibrous carbon substances are carbon nanotubes as shownin FIG. 5C (see FIG. 1E).

EXAMPLE 3

In Example 3, catalytic particles are arranged on a substrate by the gasdeposition method, without using a mask, (as an example). FIG. 11illustrates a method of producing an electron emission device of Example3.

(Process 1)

Ti with a thickness of 5 nm, Pt with a thickness of 50 nm, and Ti with athickness of 5 nm are formed on the substrate in this order by the vapordeposition method (see FIG. 11A).

(Process 2)

The catalytic particles 4 are arranged in an array on the substrate 1 bythe gas deposition method (FIG. 11B). The conditions for formation andarranging of the particles in an array are as follows.

Means for evaporating catalyst: resistance heating sublimation method(heating at 1400° C.)

Raw material for catalyst: mixture of Pd and Co

Pressure in forming chamber: 50000 Pa

Pressure in arraying chamber: 100 Pa

Distance d from evaporation portion to transport tube: 10 mm

Shape of employed nozzle: 0.5 mm φ

Movement speed of stage: 10 cm/sec

Distance L between outlet of nozzle and substrate: 10 mm

The catalytic particles 4 with a size of about 10 nm are arranged on thesubstrate 1 at intervals of about 1 μm under the above-describedconditions (see FIG. 11B).

(Process 3)

A photo-resist pattern 111 is formed in such a manner that an end faceof a region where the catalytic particles 4 are arranged in an array onthe substrate in the process 2 is exposed (see FIG. 11C). Next, etchingof the electrode is performed so that the gate electrode 2 and thecathode 3 are divided (see FIG. 11D).

(Process 4)

The resist pattern 111 is then removed. Thus, the graphite nanofibersare formed using the catalyst as a nucleus in a manner similar to theprocess 5 of Example 1 (see FIG. 11E).

EXAMPLE 4

In accordance with an Example 4 of the present invention, an imagedisplay device containing a plurality of the cold cathodes disposedtherein will be described with reference to FIGS. 8, 9, and 10. In FIG.8, an electron source substrate 81, wirings 82 in the X-direction,wirings 83 in the Y-direction, electron-emitting devices 84 constructedaccording to the present invention, and connecting wires 85 are shown.

Referring to the electron source substrate 81, a Ti/Pt/Ti electrode isvapor-deposited on a substrate by sputtering similarly to the method ofExample 3 shown in FIG. 11. Thereafter, catalytic particles (not shownin FIGS. 8, 9, and 10) are arranged while moving the substrate (stage).The moving direction of the stage is substantially parallel to theY-directional wires (input signal lines). The moving speed of the stageis set at about 10 cm/sec. and the shape of employed nozzle (outlet ofthe nozzle) is approximately 0.5 mmφ.

Subsequently, masking and etching are carried out according tophotolithography, so that an end face on a (gate electrode side) of aregion where the particles are arranged in an array is exposed. Theresist is removed, and the graphite nanofibers are grown by a thermalCVD method.

In FIG. 8, the m X-directional wirings 82 comprise wirings Dx1, Dx2, . .. Dxm. Each wiring is formed by vapor deposition, had a thickness ofabout 1 μm and a width of about 300 μm, and is made of an aluminum typematerial. The material for the wirings, the film-thickness, and thefilm-width are predetermined in accordance with predetermined designcriteria. The Y-directional wirings 83 comprise n wirings Dy1, Dy2, . .. Dy3 each having a thickness of 0.5 μm and a width of 100 μm. Thewirings are formed in a manner similar to that for the X-directionalwirings 82. Interlayer insulation layers (not shown) are providedbetween the m X-directional wirings 82 and the n Y-directional wirings83 (both m and n are positive integers) to electrically isolate thewirings 82 and 83 from each other. The X-directional wirings 82 and theY-directional wirings 83 are led-out (extend externally from the devicefor use) as external terminals (Dox1 to Doxm and Doy1 to Doyn).

Paired electrodes (not shown) of the electron emitting devices 84 ofthis Example are connected by means of the m X-directional wirings 82,the n Y-directional wirings 83, and the connecting wirings 85 made of aconductive metal or the like.

A scanning signal applying means (not shown) which applies a scanningsignal to select a line of the electron-emitting devices of this Examplearranged in the X-direction is connected to the X-directional wirings82. On the other hand, a modulation signal generating means (not shown)for modulating each row of the electron-emitting devices 84 of thisExample arranged in the Y-direction in correspondence with an inputsignal is connected to the Y-directional wirings 83. As a drive voltageto be applied to each electron-emitting device 84, the differencevoltage between the scanning signal applied to the device and themodulation signal applied to the device is supplied. In this Example,Y-directional wirings are set as a high potential side and X-directionalwirings are set as a low potential side.

According to the above-described configuration, the devices can beindividually selected and can be independently driven by use of a simplematrix array.

An image display device using an electron source in such a simple matrixarray will be described with reference to FIG. 9. FIG. 9 shows a displaypanel 97 of an image display device using soda lime glass as a materialfor a glass substrate.

In FIG. 9, an electron source substrate 81 having a plurality of theelectron emitting devices 84, and a rear plate 91 having the electronsource substrate 81 affixed thereto are shown, as is a face plate 96comprising a glass substrate 93, a fluorescent film 94, and a metal back95 formed on an inner surface of the glass substrate 93. To a supportframe 92, the rear plate 91 and the face plate 96 are bonded by use offrit glass or the like. Reference numeral 97 designates an envelopewhich is formed by baking in a temperature range of about 400° C. to450° C. under a vacuum condition for about 10 minutes for sealing, andwhich comprises the components 96, 92, and 91.

The electron-emitting devices 84 correspond to electron-emitting regionsin FIG. 9. Moreover, in FIG. 9, the X-directional wirings 82 and theY-directional wirings 83 are connected to paired electrodes of theelectron-emitting devices of the present invention. The envelope 97comprises the face plate 96, the support frame 92, and the rear plate91, as described above. Preferably, the envelope 97 further comprises asupporting member (not shown), also referred to as a spacer, disposedbetween the face plate 96 and the rear plate 91, and thereby has astructure having sufficient strength for withstanding atmosphericpressure.

The metal back 95 is formed by depositing A1 by a vacuum depositionmethod or the like, on the florescent film 94, after the fluorescentfilm 94 is prepared and a surface on an inner side of the fluorescentfilm 94 is smoothing-processed (typically, referred to as filming).

Referring to the face plate 96, a transparent electrode (not shown) isformed on an outer side surface of the fluorescent film 94 to enhancethe electroconductivity of the fluorescent film 94.

For the above-described sealing, in the case of a color display,respective color fluorescent members need to correspond to theelectron-emitting devices. Thus, sufficient and accurate positioning ofthe components is necessary.

In this Example, electrons are emitted from the cathode electrodetowards the gate electrode. Thus, the corresponding fluorescent memberis disposed in the position 200 μm shifted from right above theelectron-emitting device, when the anode voltage was 8 kV and thedistance between the anodes was 2 mm.

A scanning circuit 102 will now be described. As shown in FIG. 10, thescanning circuit 102 is provided with M switching elements insidethereof (the elements are represented by S1 to Sm in FIG. 10). Eachswitching element selects either an output voltage from DC voltagesource Vx or 0(V)(ground level), and is connected to terminals Doxl toDoxm of a display panel 101. The respective switching elements S1 to Smare operated based on a control signal Tscan output from control circuit103, and can be formed by combining switching elements such as FETs.

The DC voltage source Vx is set in such a manner that it outputs aconstant voltage at which a drive voltage to be applied toelectron-emitting devices not scanned becomes lower than the thresholdvoltage required for electron emission, based on the threshold voltagecharacteristic of the electron-emission devices of the presentinvention.

The control circuit 103 has a function of matching operations of therespective units 104, 105, and 102, so that appropriate display isachieved based on an image signal input from the outside. The controlcircuit 103 generates control signals Tscan, Tsft, and Tmry for therespective units 102, 104, and 105, based on a signal from a synchronoussignal separation circuit 106.

The synchronous signal separation circuit 106 is provided for separationof a synchronous signal component and a luminance signal component froma television signal (by, e.g., the NTSC system) input from the outside,and can be formed by use of a known frequency separation (filter)circuit or the like. The synchronous signal separated (divided) by thesynchronous signal separation circuit 106 comprises a verticalsynchronous signal and a horizontal synchronous signal, although forconvenience, the only signal Tsync representing those signals is shownin the drawing. The luminance signal component of an image separatedfrom the above-described television signal is shown as a DATA signal,for convenience. The DATA signal is input to a shift resistor 104.

The shift resistor 104 is provided for serial/parallel conversion of theDATA signals input serially in time-series for each line of an image,and is operated based on the control signal Tsft sent from the controlcircuit 103 (in other words, the control signal Tsft functions as ashift clock for the shift resistor 104). The data on one line of theserial/parallel converted image (equivalent to the drive data for nelectron-emission devices) is output as n parallel signals Idl to Idnfrom the photoresistor 104.

A line memory 105 is a storage unit for storing the data on one line ofan image for a required time, and stores the contents of the signals Id1to Idn, if necessary, based on the control signal Tmry sent from thecontrol circuit 103. The stored contents are output as I d′1 to I d′n,and input to a modulation signal generator 107.

The modulation signal generator 107 is a signal source for driving andmodulating the electron emission devices of the present inventioncorresponding to the image data I d′1 to I d′n, respectively. The outputsignals from the modulation signal generator 107 are applied to theelectron-emission devices (not shown in FIG. 10) according to thepresent invention in the display panel 101 via terminals Doyl to Doyn.

The electron-emission devices which can be applied according to thepresent invention preferably have the following basic characteristicswith respect to the emission current Ie. That is, a definite thresholdvoltage Vth exists, and the electron emission is caused only when avoltage higher than Vth is applied. For a voltage higher than thethreshold for the electron emission, the emission current changes withthe voltage applied to the electron-emission device. Thus, when a pulsedvoltage is applied to the electron-emission devices of the presentinvention, for example, such as when a voltage lower than the thresholdfor the electron emission is applied, no electron emission is caused. Onthe other hand, when a voltage higher then the threshold for theelectron emission is applied, an electron beam is output. In this case,it is possible that the intensity of the electron beam can be controlledby changing the pulse height Vm. Moreover, the total electric charge ofthe output electron beam can be controlled by changing the pulse width.

Referring to a system of modulating an electron emission devicecorrespondingly to an input signal, a voltage-modulation system, apulse-width modulation system, or another suitable modulation system maybe employed. When the voltage modulation system is carried out, avoltage modulation system circuit for generating voltage pulses with aconstant length, and appropriately modulating the pulse heightsdepending on the input data can be employed as the modulation signalgenerator 107.

To carry out the pulse-width modulation system, a pulse-width modulationsystem circuit for generating voltage pulses with a constantpulse-height, and appropriately modulating the voltage pulse-widthsdepending on the input data can be employed as the modulation signalgenerator 107. As the shift resistor 104 and the line memory 105,digital signal systems were used.

In this Example, as the modulation signal generator 107, for example, aD/A converter circuit may be used, and an amplifier circuit may beadded, if necessary. In the case of the pulse-width modulation system,for example, the combination of a high speed oscillator, a counter forcounting the number of waves output from the oscillator, and acomparator for comparing the output from the counter and the output fromthe storage device was used.

The configuration of the image display device described herein is butone example of an image display device to which the present inventioncan be applied. Various modifications may be carried out based on thetechnical idea of the present invention. With regard to the inputsignal, the NTSC system was referred to above. However, the input signalis not necessarily limited to this system. In addition to PAL and SECANsystems and so forth, a TV signal system of which the TV signalcomprises a greater number of scanning lines than that of theabove-mentioned systems (for example, high-definition television systemssuch as the MUSE system or the like) can be adopted.

As described above, during use of the electron-emission device producedaccording to the method of the present invention, an electric field canbe applied easily to the respective fibers, so that electron emissioncan be caused from the respective fibers. Thus, the density of theelectron release points in a cold cathode can be increased. Moreover,the voltage required for the electron emission can be reduced. The imagedisplay device comprises an electron source having the electron-emittingdevices, and an image is formed based on an input signal. Thus, ahigh-quality image display device such as a color flat television setcan be realized.

While the present invention has been described with reference to whatare presently considered to be the preferred embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments. To the contrary, the invention is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims. The scope of the following claims is to beaccorded the broadest reasonable interpretation so as to encompass allsuch modifications and equivalent structures and functions.

1. A method of producing a fiber, the method comprising the steps of:introducing catalytic particles originally formed in a particle-formingchamber into an arraying chamber together with a carrier gas, to causethe catalytic particles to become arranged on a substrate disposed inthe arraying chamber; and growing fibers, each including carbon as amajor component, based on the catalytic particles arranged on thesubstrate, wherein the fibers grow by heating the catalytic particlesarranged on the substrate in an atmosphere containing carbon.
 2. Amethod of producing a fiber according to claim 1, wherein a material ofthe catalytic particles is selected from the group consisting of Pd, Pt,Ni, Co, Fe, Cr, and mixtures of at least two of these materials.
 3. Amethod of producing a fiber according to claim 1, wherein a material ofthe catalytic particles includes one of Pd and Pt as a major component.4. A method of producing a fiber according to claim 1, wherein eachfiber including carbon as a major component is a fiber selected from thegroup consisting of a graphite nanofiber, a carbon nanotube, anamorphous carbon fiber, and mixtures of at least two thereof.
 5. Amethod of producing a fiber according to claim 1, wherein a plurality ofthe fibers are formed on the substrate, and have a relationship definedby W≧½H, wherein W represents an average distance between the portionsbonded to the substrate of neighboring fibers, and H represents anaverage thickness of the fibers.
 6. A method of producing a fiberaccording to claim 1, wherein a plurality of the fibers are formed onthe substrate, and have a relationship defined by W≧2H, wherein Wrepresents an average distance between the portions bonded to thesubstrate of neighboring fibers, and H represents an average thicknessof the fibers.
 7. A method of producing a fiber, comprising the stepsof: (A) preparing a catalytic material in a first chamber; (B) arranginga substrate in a second chamber; (C) setting a pressure in the firstchamber to be higher than that in the second chamber, to cause thecatalytic material prepared in the first chamber to be paused from thefirst chamber to the second chamber and collide with the substrate sothat the catalytic material becomes arranged on the substrate; and (D)heating the catalytic material arranged on the substrate while thecatalytic material is in contact with a gas including a carbon compound,to thereby cause fibers each including carbon as a major component to beformed on the substrate.
 8. A method of producing a fiber according toclaim 7, wherein the catalytic material prepared in the first chambercomprises a plurality of catalytic particles dispersed in the gasinitially present in the first chamber.
 9. A method of producing a fiberaccording to claim 7, wherein the catalytic material is paused from thefirst chamber to the second chamber through a transport tube connectedto a nozzle disposed in the second chamber, and the catalytic materialpasses into the second chamber through the nozzle.
 10. A method ofproducing a fiber according to claim 7, wherein a volume of the secondchamber is maintained in a reduced pressure state relative to a pressurestate in a volume of the first chamber.
 11. A method of producing afiber according to claim 7, wherein the catalytic material is selectedfrom the group consisting of Pd, Pt, Ni, Co, Fe, Cr, and mixtures of atleast two thereof.
 12. A method of producing a fiber according to claim7, wherein each fiber including carbon as a major component is selectedfrom a graphite nanofiber, a carbon nanotube, an amorphous carbon fiber,and mixtures of at bait two thereof.
 13. A method of producing a fiberaccording to claim 7, wherein each fiber including carbon as a majorcomponent has a plurality of graphenes.
 14. A method of producing afiber according to claim 13, wherein a plurality of the graphenes ofeach fiber are laminated in a non-parallel relationship relative to anaxis of the fiber.
 15. A method of producing a fiber according to claim7, wherein the catalytic material collides with the substrate in aparticulate state.
 16. A method of producing a fiber according to claim7, wherein the catalytic material is transported together with the gasintroduced in the first chamber, into the second chamber.
 17. A methodof producing a fiber according to any one of claims 8 and 16, whereinthe gas in the first chamber is a non-oxidizing gas.
 18. A method ofproducing an electron-emitting device, comprising the steps of: forminga cathode electrode on a substrate; and forming a fiber by a methodcomprising the steps of introducing catalytic particles originallyformed in a particle-forming chamber into an arraying chamber togetherwith a carrier gas, to cause the catalytic particles to become arrangedon a substrate disposed in the arraying chamber, and growing fibers,each including carbon as a major component, based on the catalyticparticles arranged on the substrate, wherein the fibers grow by heatingthe catalytic particles arranged on the substrate in an atmospherecontaining carbon.
 19. A method of producing an electron-emittingdevice, comprising the steps of: forming a cathode electrode on asubstrate; and forming a fiber by a method comprising the steps of (A)preparing a catalytic material in a first chamber, (B) arranging asubstrate in a second chamber, (C) pressurizing the first chamber to ahigher pressure than that in the second chamber to cause the catalyticmaterial to be paused from the first chamber to the second chamber andto collide with the substrate so that the catalytic material becomes aplurality of catalytic particles arranged on the substrate, and (D)heating the catalytic particles arranged on the substrate in a gaseousatmosphere including a carbon compound, to cause at learnt one fiberincluding carbon as a major component to be formed on the substrate. 20.A method of producing an electron source comprising a plurality ofelectron-emitting devices, wherein each electron-emitting device isproduced according to a method comprising the steps of: forming acathode electrode on a substrate; and forming a fiber by a methodcomprising the steps of introducing catalytic particles originallyformed in a particle-forming chamber into an arraying chamber togetherwith a carrier gas, to cause the catalytic particles to became arrangedon a substrate disposed in the arraying chamber, and growing fibers,each including carbon as a major component, based on the catalyticparticles arranged on the substrate, wherein the fibers grow by heatingthe catalytic particles arranged on the substrate in an atmospherecontaining carbon.
 21. A method of producing an image display devicecomprising an electron source and a light-emitting member, wherein theelectron source is produced by a method according to claim
 20. 22. Amethod of producing an electron source comprising a plurality ofelectron-emitting devices, wherein each electron-emitting device isproduced according to a method comprising the steps of: forming acathode electrode on a substrate; and forming a fiber by a methodcomprising the steps of (A) preparing a catalytic material in a firstchamber, (B) arranging a substrate in a second chamber, (C) pressurizingthe first chamber to a higher pressure than that in the second chamberto cause the catalytic material to be passed from the first chamber tothe second chamber and to collide with the substrata so that thecatalytic material becomes a plurality of catalytic particles arrangedon the substrate, and (D) heating the catalytic particles arranged onthe substrate in a gaseous atmosphere including a carbon compound, tocause at learnt one fiber including carbon as a major component to beformed on the substrate.
 23. A method of producing an image displaydevice comprising an electron source and a light-emitting member,wherein the electron source is produced by a method according to claim22.